The interfacial Dzyaloshinskii-Moriya interaction and spin-orbit torque driven domain wall motion in Co/Ni multi-layers with a Ptx(Ir,Au)1−x seedlayer

We use Kerr microscopy to characterize magnetic domain walls in Co/Ni based magnetic nanowires grown on a Pt seedlayer with a thin Ptx(Ir,Au)1−x buffer layer. The buffer layer composition enables control of the interfacial DMI vector as measured from the asymmetric bubble expansion technique while the thicker Pt seedlayer is expected to govern the spin Hall angle. Additions of either Ir or Au to the Pt buffer layer give rise to a marked drop in the interfacial DMI vector. The efficiency of current induced magnetic domain wall motion in nanowires shows a direct relation to DMI across the composition spectrum. This correlation is discussed in the context of future spintronic devices as a mechanism for engineering the spin-orbit coupling properties of complex magnetic multi-layers.